Implantable microneedle and manufacturing method therefor

Abstract

The present invention provides an implantable microneedle and a manufacturing method therefor. An implantable microneedle according to the present invention comprises a coating layer for covering at least one part of the surface of a tip part of the microneedle. When exposed to moisture, the coating layer can be separated from the tip part of the microneedle and thus be implanted.

What is claimed is: 
     
       1. A method for manufacturing a microneedle having a coating layer on a surface of a tip, the method comprising:
 dripping a swellable polymer solution on the tip of the microneedle to form the coating layer thereon; 
 wherein the method further comprises, before forming the coating layer, coating a sacrificial layer solution on a surface of the tip of the microneedle to form a sacrificial layer thereon, 
 wherein forming the coating layer includes dripping the swellable polymer solution on the sacrificial layer to form the coating layer thereon, 
 wherein the sacrificial layer has been dissolved in water before the swellable polymer based coating layer has been dissolved in water. 
 
     
     
       2. The method of  claim 1 , wherein the dripping of the swellable polymer solution is performed while the microneedle is tilted at an angle greater than 0° and smaller than 90° with respect to a ground. 
     
     
       3. The method of  claim 1 , wherein forming the coating layer includes forming the coating layer having an asymmetrical structure with respect to a central axis of the microneedle. 
     
     
       4. The method of  claim 3 , wherein the coating layer is thicker as the coating layer extends downwardly. 
     
     
       5. The method of  claim 1 , wherein the swellable polymer solution contains at least one polymer selected from a group consisting of gelatin, chitosan, collagen, hyaluronic acid and chondroitin sulfate. 
     
     
       6. The method of  claim 1 , wherein the microneedle has a shape having a cylindrical body and a conical tip. 
     
     
       7. The method of  claim 6 , wherein in forming the coating layer, a difference between an inclination of a surface of the body and an inclination of a surface of the tip allows the dripped swellable polymer solution to be prevented from flowing downward along the body of the microneedle. 
     
     
       8. The method of  claim 1 , wherein in forming the coating layer, at least a portion of a surface of the sacrificial layer is temporarily dissolved in the dripped swellable polymer solution to prevent the swellable polymer solution from flowing downwards along the microneedle, such that the coating layer is formed only on the sacrificial layer. 
     
     
       9. The method of  claim 8 , wherein the sacrificial layer solution contains at least one of a monosaccharide or a water-soluble polymer having a molecular weight lower than 10k. 
     
     
       10. An implantable microneedle comprising:
 a tip; and 
 a swellable polymer based coating layer covering at least a portion of a surface of the tip, 
 wherein the coating layer is removable from the microneedle in a body environment; 
 wherein the implantable microneedle further comprises a sacrificial layer disposed between the surface of the tip of the microneedle and the swellable polymer based coating layer, wherein the sacrificial layer covers at least a portion of the tip surface of the microneedle, wherein the sacrificial layer has been dissolved in moisture before the swellable polymer based coating layer has been dissolved in moisture, 
 wherein the coating layer covers at least a portion of the sacrificial layer. 
 
     
     
       11. The implantable microneedle of  claim 10 , wherein the swellable polymer includes at least one selected from a group consisting of gelatin, chitosan, collagen, hyaluronic acid and chondroitin sulfate. 
     
     
       12. The implantable microneedle of  claim 11 , wherein the swellable polymer is crosslinked to a degree such that at least a portion of an interface or a surface thereof is dissolved in a short time in moisture. 
     
     
       13. The implantable microneedle of  claim 10 , wherein the microneedle has a shape having a cylindrical body and a conical tip. 
     
     
       14. The implantable microneedle of  claim 10 , wherein the coating layer has an asymmetrical structure with respect to a central axis of the microneedle. 
     
     
       15. The implantable microneedle of  claim 14 , wherein the coating layer has one portion thicker than the other portion thereof. 
     
     
       16. The implantable microneedle of  claim 10 , wherein the sacrificial layer is made of at least one of a monosaccharide or a water-soluble polymer having a molecular weight lower than 10k. 
     
     
       17. The implantable microneedle of  claim 10 , wherein when inserting the microneedle into the body and removing the microneedle therefrom, the coating layer is separated from the microneedle and thus is implanted in the body. 
     
     
       18. The implantable microneedle of  claim 10 , wherein the coating layer contains a drug therein. 
     
     
       19. The implantable microneedle of  claim 18 , wherein the microneedle acts as implantable drug delivery means or an implantable tissue adhesive.